The present invention relates to a cross car beam for a vehicle.
Generally, the cross car beam is arranged inside an automotive instrument panel while fixing both car beam's ends in the vehicle-width direction to pillar members on both lateral sides of a vehicle body or a dash panel. In this state, the cross car beam performs a role to support a steering unit, the instrument panel and so on. Therefore, in view of ensuring beam's rigidity meeting such a role, the cross car beam is generally made from high rigid materials, such as steels and manganese.
Japanese Patent Application Laid-open No. 2002-211441 discloses a cross car beam made of synthetic resin. In the above art, the disclosed cross car beam is provided, on its attachment surfaces to the vehicle body, with additional ribs. Alternatively, the attachment surfaces are increased in thickness. In this way, the attachment surfaces are reinforced to increase the strength of the cross car beam.
In the case of the former cross car beam of steels or the like, it should be noted that the total weight of the cross car beam is increased disadvantageously. While, in the case of the latter cross car beam made of synthetic resin, the usage amount of synthetic resin is increased due to the provision of the thickened ribs or additional ribs, thereby raising the beam's manufacturing cost. Additionally, if a cross car beam is provided, on both sides thereof, with “vent” blowout ports, there arises a possibility that the cross car beam is weaker in the vicinity of the blowout ports.
It is generally noted that the cross car beam has its intermediate part (in the vehicle-width direction) supported by a floor panel etc. on the side of the vehicle body through the intermediary of a support stay. As previously mentioned, in view of the requirements to support the instrument panel and the steering unit, it is necessary to provide a cross car beam with high rigidity. For this purpose, such a cross car beam is provided with a high rigid attachment part for fixation with a support member on the side of the vehicle body. This attachment part is formed by a high rigid material, such as steel and manganese. During assembly, the attachment part of the cross car beam is fixed to an end of the support stay (as the above support member), while the other end of the support stay is fixed to a floor panel of the vehicle body. In this way, the cross car beam is carried by the vehicle body (see Japanese Patent Application Laid-open No. 2002-284018).
It should be noted, however that a supporting structure for a cross car beam in accordance with the above prior art has various problems to be solved. First in the case of an attachment part of steel, the weight of the cross car beam is increased. Second, in the case of an attachment part of manganese, the manufacturing cost of the cross car beam is also elevated. Third when a cross car beam and its attachment part are formed by resinous materials, there arises a possibility that the supporting rigidity of the cross car beam is lowered in comparison with that of the cross car beam made of steel, manganese or the like. Fourth, the cross car beam carries a steering unit etc., an air conditioning unit for feeding warm or cool wind (air) into a vehicle cabin is arranged independently of such a cross car beam (see Japanese Patent Application Laid-open No. 2001-328421).
Japanese Patent Application Laid-open No. 2002-284018 discloses a cross car beam that is equipped, on its peripheral surface, with steering support brackets for supporting a steering unit. During assembly, after forming a main body for the cross car beam, attachment bolts for supporting the steering unit are attached to the steering support brackets of the cross car beam. Thus, the steering support brackets support the steering unit through the attachment bolts. As the steering unit is generally heavy, it is necessary for the steering support brackets to have great mechanical strength. However, as the above-mentioned steering support brackets are thickened in view of ensuring high rigidity corresponding to the required mechanical strength, the cost of components of the cross car beam is apt to rise disadvantageously.
Additionally, it is noted that the above prior art (Japanese Patent Application Laid-open No. 2002-284018) requires fitting the attachment bolts to the steering support brackets after providing the cross car beam with the steering support. As a result, the manufacturing of the cross car beam of the prior art has a tendency to waste time and labor.
As mentioned previously, the cross car beam is arranged inside the instrument panel generally. In connection, the cross car beam is generally provided, on the assistant driver's side, with an air-bag attachment member for installation of an air-bag unit. This air-bag attachment member has to be provided with a designated strength because it may be subjected, during a vehicle collision, to a collision impact transmitted from a passenger through an air bag. As previously mentioned, as the cross ear beam is adapted to support an instrument panel and a steering unit, the cross car beam and the air-bag attachment member are formed by the use of high rigid materials, such as steels (see Japanese Patent Application Laid-open No. 10-11984), which high rigid materials increase the total weight of the cross car beam disadvantageously. Moreover, in the case of forming a cross car beam and an air-bag attachment member of synthetic resin, which is lighter in weight than steel, it is necessary to thicken the cross car beam and the air-bag attachment member in view of their rigidity, thereby raising the material cost in manufacturing.